Alleles of IL-17A and IL-17F genes were reported to be associated with many inflammatory and autoimmune disorders in Asian patients. Serum level and mRNA of IL-17A in peripheral blood mononuclear cells were reported to be significantly higher in MG patients than in healthy controls. In experimental autoimmune myasthenia gravis (EAMG) animals, IL-17 may have effects on the severity of MG. This study investigated the association between four SNPs of IL-17A and IL-17F gene (rs8193036, rs2275913 and rs3748067 in IL-17A; rs763780 in IL-17F) and MG in Chinese patients. The allele frequencies were compared between 480 MG patients and 487 healthy controls, between each MG subgroup and the control group, and between each pairs of MG subgroups. Subgroups were specified by clinical features (onset age, gender, thymoma, AChRAb and muscle involvement at onset) and maximal severity during the follow-up. No associations were found between the four SNPs of IL-17A and IL-17F gene and MG in Chinese patients.